Question

Sasha noticed that the graph of the sales of yearbooks represented a proportional relationship. How could she have calculated the constant of proportionality by looking at the graph?

Answer 1

She could divide any y-value by its corresponding x-value

Answer 2

Sasha can look at the graph and check to see that when she plots the points on the graph, they end up as a straight line. She can also draw a table to test the values and see if when you divide y/x you get the same answer for all of them.